Automated sniffer apparatus and method for monitoring computer systems for unauthorized access

ABSTRACT

An apparatus for wireless communication including an automated intrusion detection process is provided. The apparatus has a portable housing, which may have a length no greater than 1 meter, a width no greater than 1 meter, and a height of no greater than 1 meter. A processing unit (e.g., CPU) is within the housing. One or more wireless network interface devices are within the housing and are coupled to the processing unit. The apparatus has an Ethernet (or like) network interface device within the housing and coupled to the processing unit. A network connector is coupled to the Ethernet network device. One or more memories are coupled to the processing unit. A code is directed to perform a process for detection of a wireless activity within a selected local geographic region. According to a specific embodiment, the wireless activity is derived from at least one authorized device or at least an other device. A code is directed to receiving at least identity information associated with the wireless activity from the detection process in a classification process. A code is directed to labeling the identity information into at least one of a plurality of categories in the classification process. Depending upon the embodiment, other codes may exist to carry out the functionality described herein.

This present application is a continuation of U.S. patent applicationSer. No. 13/399,626, titled “Automated Sniffer Apparatus and Method forMonitoring Computer Systems for Unauthorized Access”, filed Feb. 17,2012, commonly assigned, and hereby incorporated by reference for allpurposes, which in turn is a continuation of U.S. patent applicationSer. No. 11/970,532, titled “Automated Sniffer Apparatus and Method orMonitoring Computer Systems for Unauthorized Access”, filed Jan. 8,2008, now abandoned, commonly assigned, and hereby incorporated byreference for all purposes, which in turn is a continuation of U.S.patent application Ser. No. 10/931,585, titled “Automated SnifferApparatus and Method for Monitoring Computer Systems or UnauthorizedAccess”, filed Aug. 31, 2004 (now U.S. Pat. No. 7,339,914, issued Mar.4, 2008), commonly assigned, and hereby incorporated by reference forall purposes, which is turn claims priority to U.S. ProvisionalApplication No. 60/543,631, titled “An Automated Method and an RF SensorSystem for Wireless Unauthorized Transmission, Intrusion Detection andPrevention,” filed Feb. 11, 2004, commonly assigned, and herebyincorporated by reference for all purposes. This present application isa continuation of U.S. patent application Ser. No. 12/419,300, titled“Automated Method and System for Monitoring Local Area Computer Networksfor Unauthorized Wireless Access”, filed Apr. 7, 2009, commonlyassigned, and hereby incorporated by reference for all purposes, whichin turn is a continuation of U.S. patent application Ser. No.10/931,926, titled “Automated Method and System for Monitoring LocalArea Computer Networks for Unauthorized Wireless Access”, filed Aug. 31,2004 (now U.S. Pat. No. 7,536,723, issued May 19, 2009), commonlyassigned, and hereby incorporated by reference for all purposes, whichin turn claims priority to U.S. Provisional Application No. 60/543,631,titled “An Automated Method and an RF Sensor System for WirelessUnauthorized Transmission, Intrusion Detection And Prevention,” filedFeb. 11, 2004, commonly assigned, and hereby incorporated by referencefor all purposes.

This present application is also related to U.S. patent application Ser.No. 10/931,926, titled “Automated Method and System for Monitoring LocalArea Computer Networks for Unauthorized Wireless Access”, filed Aug. 31,2004 (now U.S. Pat. No. 7,536,723, issued May 19, 2009), commonlyassigned, and hereby incorporated by reference for all purposes, whichclaims priority to U.S. Provisional Application No. 60/543,631, titled“An Automated Method and an RF Sensor System for Wireless UnauthorizedTransmission, Intrusion Detection And Prevention,” filed Feb. 11, 2004,commonly assigned, and hereby incorporated by reference for allpurposes.

BACKGROUND OF THE INVENTION

The present invention relates generally to wireless computer networkingtechniques. More particularly, the invention provides a snifferapparatus and method for providing intrusion detection for local areawireless networks according to a specific embodiment. Merely by way ofexample, the invention has been applied to a computer networkingenvironment based upon the IEEE 802.11 family of standards, commonlycalled “WiFi.” But it would be recognized that the invention has a muchbroader range of applicability. For example, the invention can beapplied to Ultra Wide Band (“UWB”), IEEE 802.16 commonly known as“WiMAX”, Bluetooth, and others.

Computer systems proliferated from academic and specialized scienceapplications to day to day business, commerce, information distributionand home applications. Such systems include personal computers, whichare often called “PCs” for short, to large mainframe and server classcomputers. Powerful mainframe and server class computers run specializedapplications for banks, small and large companies, e-commerce vendorsand governments. Smaller personal computers can be found in many if notall offices, homes, and even local coffee shops. These computersinterconnect with each other through computer communication networksbased on packet switching technology such as the Internet protocol orIP. The computer systems located within a specific local geographic areasuch as office, home or other indoor and outdoor premises interconnectusing a Local Area Network, commonly called, LAN. Ethernet is by far themost popular networking technology for LANs. The LANs interconnect witheach other using a Wide Area Network called “WAN” such as the famousInternet. Although much progress occurred with computers and networking,we now face a variety of security threats on many computing environmentsfrom the hackers connected to the computer network. The application ofwireless communication to computer networking further accentuates thesethreats.

As merely an example, the conventional LAN is usually deployed using anEthernet based infrastructure comprising cables, hubs switches, andother elements. A number of connection ports (e.g., Ethernet ports) areused to couple various computer systems to the LAN. A user can connectto the LAN by physically attaching a computing device such as laptop,desktop or handheld computer to one of the connection ports usingphysical wires or cables. Other computer systems such as databasecomputers, server computers, routers and Internet gateways also connectto the LAN to provide specific functionalities and services. Oncephysically connected to the LAN, the user often accesses a variety ofservices such as file transfer, remote login, email, WWW, databaseaccess, and voice over IP. Security of the LAN often occurs bycontrolling access to the physical space where the LAN connection portsreside.

Although conventional wired networks using Ethernet technologyproliferated, wireless communication technologies are increasing inpopularity. That is, wireless communication technologies wirelesslyconnect users to the computer communication networks. A typicalapplication of these technologies provides wireless access to the localarea network in the office, home, public hot-spots, and othergeographical locations. As merely an example, the IEEE 802.11 family ofstandards, commonly called WiFi, is the common standard for suchwireless application. Among WiFi, the 802.11b standard-based WiFi oftenoperates at 2.4 GHz unlicensed radio frequency spectrum and offerswireless connectivity at speeds up to 11 Mbps. The 802.11g compliantWiFi offers even faster connectivity at about 54 Mbps and operates at2.4 GHz unlicensed radio frequency spectrum. The 802.11a provides speedsup to 54 Mbps operating in the 5 GHz unlicensed radio frequencyspectrum. The WiFi enables a quick and effective way of providingwireless extension to the existing LAN.

In order to provide wireless extension of the LAN using WiFi, one ormore WiFi access points (APs) connect to the LAN connection ports eitherdirectly or through intermediate equipment such as WiFi switch. A usernow wirelessly connects to the LAN using a device equipped with WiFiradio, commonly called wireless station, that communicates with the AP.The connection is free from cable and other physical encumbrances andallows the user to “Surf the Web” or check e-mail in an easy andefficient manner. Unfortunately, certain limitations still exist withWiFi. That is, the radio waves often cannot be contained in the physicalspace bounded by physical structures such as the walls of a building.Hence, wireless signals often spill outside the area of interest.Unauthorized users can wirelessly connect to the AP and hence gainaccess to the LAN from the spillage areas such as the street, parkinglot, and neighbor's premises. Consequently, the conventional securitymeasure of controlling access to the physical space where the LANconnection ports are located is now inadequate.

In order to prevent unauthorized access to the LAN over WiFi, the APimplements one or more of a variety of techniques. For example, the useris required to carry out authentication handshake with the AP (or a WiFiswitch that resides between the AP and the existing LAN) before beingable to connect to the LAN. Examples of such handshake are WirelessEquivalent Privacy (WEP) based shared key authentication, 802.1x basedport access control, 802.11i based authentication. The AP can provideadditional security measures such as encryption, firewall. Othertechniques also exist to enhance security of the LAN over WiFi.

Despite these measures, many limitations still exist. As merely anexample, a threat of an unauthorized AP being connected to the LAN oftenremains with the LANs. The unauthorized AP creates a securityvulnerability. The unauthorized AP allows wireless intruders to connectto the LAN through itself. That is, the intruder accesses the LAN andany proprietary information on computers and servers on the LAN withoutthe knowledge of the owner of the LAN. Soft APs, ad hoc networks, andmisconfigured APs connected to the LAN also pose similar threats.Appropriate security mechanisms are thus needed to protect the LANresources from wireless intruders.

Accordingly, techniques for improving security for local area networkenvironments are highly desirable.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, techniques directed to wirelesscomputer networking are provided. More particularly, the inventionprovides a sniffer apparatus and method for providing intrusiondetection for local area wireless networks according to a specificembodiment. Merely by way of example, the invention has been applied toa computer networking environment based upon the IEEE 802.11 family ofstandards, commonly called “WiFi.” But it would be recognized that theinvention has a much broader range of applicability. For example, theinvention can be applied to UWB, WiMAX (802.16), Bluetooth, and others.

In a specific embodiment, the present invention provides an apparatusfor wireless communication including an automated intrusion detectionprocess. The apparatus has a portable housing, which may have a lengthno greater than 1 meter, a width no greater than 1 meter, and a heightof no greater than 1 meter. A processing unit (e.g., CPU) is within thehousing. One or more wireless network interface devices are within thehousing and are coupled to the processing unit. The apparatus has anEthernet (or like) network interface device within the housing andcoupled to the processing unit. A network connector (e.g., RJ-45 socket)is coupled to the Ethernet network device. One or more memories arecoupled to the processing unit. A code is directed to perform a processfor detection of a wireless activity within a selected local geographicregion. According to a specific embodiment, the wireless activity isderived from at least one authorized device or at least an other device.A code is directed to receiving at least identity information associatedwith the wireless activity from the detection process in aclassification process. A code is directed to labeling the identityinformation into at least one of a plurality of categories in theclassification process. Depending upon the embodiment, other codes mayexist to carry out the functionality described herein.

In an alternative specific embodiment, the invention provides wirelesssniffer apparatus including an automated intrusion detection process.The apparatus has housing, which is characterized by a length no greaterthan a first dimension, a width no greater than a second dimension, anda height of no greater than a third dimension. The apparatus has aprocessing unit within the housing and one or more wireless networkinterface devices within the housing and coupled to the processing unit.The apparatus has one or more antennas coupled to the one or morewireless network interface devices. Depending upon the embodiment, theone or more antennas are adapted to protrude outside of a portion of thehousing or be within the housing or any combination of these. Theapparatus has at least one Ethernet network interface device within thehousing and coupled to the processing unit and a least one networkconnector (e.g., RJ-45 socket) coupled to the Ethernet network device.One or more memories are coupled to the processing unit. A code isdirected to perform a process for detection of a wireless activitywithin a selected local geographic region. According to a specificembodiment, the wireless activity is derived from at least oneauthorized device or at least an other device. A code is directed toreceiving at least identity information associated with the wirelessactivity from the detection process in a classification process. A codeis directed to labeling the identity information into at least one of aplurality of categories in the classification process. The apparatusalso has a code directed to testing connectivity of at least the otherdevice associated with the detected wireless activity to a local areanetwork within the selected local geographic region. A first outputindication (e.g., light, speaker) is on the housing. The first outputindication is associated with the authorized device. A second outputindication (e.g., light, speaker) is on the housing. Preferably, thesecond output indication is associated with the other device.

In yet an alternative specific embodiment, the present inventionprovides a method for installing one or more security devices over aselected local geographic region. The method includes providing awireless sniffer apparatus including an automated intrusion detectionprocess, such as those described herein. The method includes connectingthe network connector of the sniffer apparatus to the local area network(e.g., using Ethernet cable). The method includes executing computercodes directed to testing connectivity of at least an other deviceassociated with the detected wireless activity to the local area networkand outputting either the first output indication or the second outputindication based upon the detected wireless activity.

Still further, in an alternative embodiment, the invention provides anapparatus for sniffing wireless communication including an automatedintrusion detection process. The apparatus has a movable housing, whichhas a length, a width, and a height. Preferably, the housing is enclosedand portable. The apparatus has a processing unit within the housing andis preferably enclosed. The apparatus also has one or more wirelessnetwork interface devices within the housing and coupled to theprocessing unit. At least one Ethernet network interface device iswithin the housing and coupled to the processing unit. At least onenetwork connector is coupled to the Ethernet network interface deviceand one or more memories is within the housing and coupled to theprocessing unit. The processing unit is adapted to direct a process fordetection of a wireless activity within a selected local geographicregion. The wireless activity is derived from at least one authorizeddevice or at least an other device. The processing unit is adapted toreceive at least identity information associated with the wirelessactivity from the detection process in a classification process. Theprocessing unit is also adapted to label the identity information intoat least one of a plurality of categories in the classification process.Other functions described herein may also be performed via theprocessing unit.

Certain advantages and/or benefits may be achieved using the presentinvention. For example, the present technique provides an easy to useprocess that relies upon conventional computer hardware and softwaretechnologies. In some embodiments, the method and system are fullyautomated and can be used to prevent unauthorized wireless access oflocal area computer networks. The automated operation minimizes thehuman effort required during the system operation and improves thesystem response time and accuracy. In some embodiments, the method andsystem advantageously reduce or eliminate the false positives onintrusion events thereby eliminating the nuisance factor during thesystem operation. This is because the technique of the inventionintelligently distinguishes between unauthorized APs and external APs,the latter usually being the source of false positives. According tospecific embodiment, the invention provides for standalone applianceimplementation of intrusion detection system thereby providing intrusiondetection solution at a low cost and at a low or no other networkmanagement infrastructure requirement. This is particularly advantageousfor smaller network installations such as those in small offices, coffeeshops, house, apartment, etc. Additionally, the invention is compatiblewith conventional wireless and wired networking technologies withoutsubstantial modifications to conventional equipment and processesaccording to a specific embodiment. Depending upon the embodiment, oneor more of these benefits may be achieved. These and other benefits willbe described in more throughout the present specification and moreparticularly below.

Other features and advantages of the invention will become apparentthrough the following detailed description, the drawings, and theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a simplified LAN architecture that supports wirelessintrusion detection according to an embodiment of the present invention.

FIG. 1A illustrates a simplified flow diagram of an intrusion detectionmethod according to an embodiment of the present invention.

FIG. 1B is a simplified illustration of a sniffer apparatus according toan embodiment of the present invention.

FIG. 1C is a simplified flow diagram illustrating a method forinstalling the sniffer apparatus according to an embodiment of thepresent invention.

FIG. 2 shows a simplified logical flow of steps according to a method ofan embodiment of the present invention.

FIG. 3 shows a simplified logical flow of steps for maintaining the listof active APs according to an embodiment of the present invention.

FIG. 4 shows a simplified logical flow of steps in an embodiment of theLAN connectivity test according to the present invention.

FIG. 5 shows a simplified logical flow of steps in another embodiment ofthe LAN connectivity test according to the present invention.

FIG. 6 shows a simplified logical flow of steps in another embodiment ofthe LAN connectivity test according to the present invention.

FIG. 7 is a simplified system diagram according to an embodiment of thepresent invention.

FIG. 8 is a simplified system diagram according to an alternativeembodiment of the present invention.

FIG. 9 is a simplified system diagram of a standalone implementationaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, techniques for wireless computernetworking are provided. More particularly, the invention provides asniffer apparatus and method for providing intrusion detection for localarea wireless networks according to a specific embodiment. Merely by wayof example, the invention has been applied to a computer networkingenvironment based upon the IEEE 802.11 family of standards, commonlycalled “WiFi.” But it would be recognized that the invention has a muchbroader range of applicability. For example, the invention can beapplied to UWB, WiMAX (802.16), Bluetooth, and others.

FIG. 1 shows the LAN architecture that supports the intrusion detectionaccording to one embodiment of the invention. This diagram is merely anexample, which should not unduly limit the scope of the claims herein.One of ordinary skill in the art would recognize other variations,modifications, and alternatives. As shown in FIG. 1, the coretransmission infrastructure 102 for the LAN 101 comprises of Ethernetcables, hubs and switches. Other devices may also be included. Pluralityof connection ports (e.g., Ethernet ports) are provided for the variouscomputer systems to be able to connect to the LAN. One or more end userdevices 103 such as desktop computers, notebook computers, telemetrysensors etc. are connected to the LAN 101 via one or more connectionports 104 using wires (Ethernet cable) or other suitable devices. Othercomputer systems that provide specific functionalities and services arealso connected to the LAN. For example, one or more database computers105 may be connected to the LAN via one or more connection ports 108.Examples of information stored in database computers include customeraccounts, inventory, employee accounts, financial information, etc. Oneor more server computers 106 may be connected to the LAN via one or moreconnection ports 109. Examples of services provided by server computersinclude database access, email storage, HTTP proxy service, DHCPservice, SIP service, authentication, network management, etc. Therouter 107 is connected to the LAN via connection port 110 and it actsas a gateway between the LAN 101 and the Internet 111. The firewall/VPNgateway 112 protects computers in the LAN against hacking attacks fromthe Internet 111. It may additionally also enable remote secure accessto the LAN.

WiFi is used to provide wireless extension of the LAN. For this, one ormore authorized WiFi APs 113A, 113B are connected to the LAN via WiFiswitch 114. The WiFi switch is connected to the LAN connection port 115.The WiFi switch enables offloading from APs some of the complexprocedures for authentication, encryption, QoS, mobility, etc., and alsoprovides centralized management functionality for APs, making overallWiFi system scalable for large scale deployments. The WiFi switch mayalso provide additional functionalities such as firewall. One or moreauthorized WiFi AP 116 may also be directly connected to the LANconnection port 117. In this case AP 116 may itself perform necessarysecurity procedures such as authentication, encryption, firewall, etc.One or more end user devices 118 such as desktop computers, laptopcomputers, PDAs equipped with WiFi radio can now wirelessly connect tothe LAN via authorized APs 113A, 113B and 116. Although WiFi has beenprovided according to the present embodiment, there can also be othertypes of wireless network formats such as UWB, WiMax, Bluetooth, andothers.

One or more unauthorized APs can be connected to the LAN. The figureshows unauthorized AP 119 connected to the LAN connection port 120. Theunauthorized AP may not employ the right security policies. Also trafficthrough this AP may bypass security policy enforcing elements such asWiFi switch 114 or firewall/VPN gateway 112. The AP 119 thus poses asecurity threat as intruders such as wireless station 126 can connect tothe LAN and launch variety of attacks through this AP. According to aspecific embodiment, the unauthorized AP can be a rogue AP, amisconfigured AP, a soft AP, and the like. A rogue AP can be a commodityAP such as the one available openly in the market that is brought in bythe person having physical access to the facility and connected to theLAN via the LAN connection port without the permission of the networkadministrator. A misconfigured AP can be the AP otherwise allowed by thenetwork administrator, but whose security parameters are, usuallyinadvertently, incorrectly configured. Such an AP can thus allowwireless intruders to connect to it. Soft AP is usually a “WiFi” enabledcomputer system connected to the LAN connection port that also functionsas an AP under the control of software. The software is eitherdeliberately run on the computer system or inadvertently in the form ofa virus program.

The figure also shows neighbor's AP 121 whose radio coverage spills intothe area covered by LAN. The AP 121 is however not connected to theconcerned LAN 101 and is harmless from the intrusion standpoint.According to a specific embodiment, the neighbor's AP can be an AP inthe neighboring office, an AP is the laboratory not connected to theconcerned LAN but used for standalone development and/orexperimentation, an AP on the street providing free “WiFi” access topassersby and other APs, which co-exist with the LAN and share theairspace without any significant and/or harmful interferences.

A WiFi AP delivers data packets between the wired LAN and the wirelesstransmission medium. Typically, the AP performs this function either byacting as a layer 2 bridge or as a network address translator (NAT). Thelayer 2 bridge type AP simply transmits the Ethernet packet received onits wired interface to the wireless link after translating it to 802.11style packet and vice versa. The NAT AP on the other hand acts as alayer 3 (IP) router that routes IP packets received on its wiredinterface to the stations connected to its wireless interface and viceversa. The wired side and wireless side interfaces of the NAT AP thususually reside on different subnets.

The intrusion detection system according to the present invention isprovided to protect the LAN 101 from unauthorized APs and/or wirelessintruders. The system involves one or more sensor devices 122A, 122B(i.e., sniffers) placed throughout a geographic region or a portion ofgeographic region including the connection points to the LAN 101. Thesniffer is able to monitor the wireless activity in the selectedgeographic region. For example, the sniffer listens to the radio channeland capture packets being transmitted on the channel. The sniffer cyclesthrough the radio channels on which wireless communication can takeplace. On each radio channel, it waits and listens for any ongoingtransmission. In one embodiment, the sniffer is able operate onplurality of radio channels simultaneously. Whenever transmission isdetected, the relevant information about that transmission is collectedand recorded. This information comprises of all or a subset ofinformation that can be gathered from various fields in the capturedpacket such as 802.11 MAC (medium access control) header, 802.2 LLC(i.e., logical link control) header, IP header, transport protocol(e.g., TCP, UDP, HTTP, RTP etc.) headers, packet size, packet payloadand other fields. Receive signal strength (i.e., RSSI) may also berecorded. Other information such as the day and the time of the day whensaid transmission was detected may also be recorded.

According to a specific embodiment, the sniffer device can be anysuitable receiving/transmitting device capable of detecting wirelessactivity. As merely an example, the sniffer often has a smaller formfactor. The sniffer device has a processor, a flash memory (where thesoftware code for sniffer functionality resides), a RAM, two 802.11a/b/gwireless network interface cards (NICs), one Ethernet port (withoptional power over Ethernet or POE), a serial port, a power input port,a pair of dual-band (2.4 GHz and 5 GHz) antennas, and at least onestatus indicator light emitting diode. The sniffer can be built usingthe hardware platform similar to one used to built wireless accesspoint, although functionality and software will be different for asniffer device. Of course, one of ordinary skill in the art wouldrecognize other variations, modifications, and alternatives. Furtherdetails of the sniffers are provided throughout the presentspecification and more particularly below.

One or more sniffers 122A and 122B may also be provided with radiotransmit interface which is useful to perform intrusion preventionprocedures, i.e., to perform preventive action against detectedintrusion. In one specific embodiment, the sniffer is a dual slot devicewhich has two wireless NICs. These NICs can be used in a variety ofcombinations, for example both for monitoring, both form transmitting,one for monitoring and the other for transmitting etc., under thecontrol of software. In another specific embodiment, the sniffer hasonly one wireless NIC. The same NIC is shared in a time divisionmultiplexed fashion to carry out monitoring as well as defense againstintrusion. The radio transmit interface of the sniffer is also used toperform certain other transmission procedures according to someembodiments of the method of invention, for example transmission ofmarket packet in some embodiments of the LAN connectivity test,transmission of active probe packets, and the like. Each sniffer alsohas Ethernet NIC using which it is connected to the connection port 123of the LAN. The sniffers can be spatially disposed at appropriatelocations in the geographic area to be monitored for intrusion by usingone or more of heuristics, strategy and calculated guess. Alternatively,a more systematic approach using an RF (radio frequency) planning toolis used to determine physical locations where said sniffers need to bedeployed according to an alternative embodiment of the presentinvention.

In a specific embodiment, the sniffer device captures wireless activity.Such wireless activity includes, among others, transmission of control,management or data packet between an AP and a wireless station or amongwireless stations, and communication for establishing wirelessconnection between an AP and a wireless station often calledassociation. Depending upon the embodiment, the invention also providescertain methods for monitoring wireless activity in selected geographicregions.

According to a specific embodiment, the present invention provides amethod for monitoring a wireless communication space (e.g., officespace, home, apartments, government buildings, warehouses, hot-spots,commercial facilities etc.) occupied by one or more computer networkswhich may be outlined as follows.

1. Provide a geographic region;2. Operate a local area network in a selected portion of the geographicregion;3. Monitor a selected local geographic region in the geographic regionusing one or more sniffer devices;4. Detect a wireless activity from at least one authorized device, atleast one unauthorized device, or at least one external device, withinthe selected local geographic region using at least one of the snifferdevices from the one or more sniffer devices;5. Receive at least identity information (e.g., source information,destination information, MAC address) associated with the wirelessactivity in a classification process;6. Label the identity information into at least one of a plurality ofcategories;7. Transfer an indication associated with the identify information to aprevention process; and8. Perform other steps, as desired.

The above sequence of steps provides methods according to an embodimentof the present invention. As shown, the method uses a combination ofsteps including a way of detecting for an intrusion using wirelesscomputer networks. In preferred embodiments, the present invention alsoincludes an automated method for transferring an indication of anintrusion to a prevention process, which would preferably stop theintruding device before any security problems or the like. Many othermethods and system are also included. Of course, other alternatives canalso be provided where steps are added, one or more steps are removed,or one or more steps are provided in a different sequence withoutdeparting from the scope of the claims herein. Additionally, the variousmethods can be implemented using a computer code or codes in software,firmware, hardware, or any combination of these. Depending upon theembodiment, there can be other variations, modifications, andalternatives. Further details of the present method can be foundthroughout the present specification and more particularly below.

FIG. 1A illustrates a simplified flow diagram of an intrusion detectionmethod according to an embodiment of the present invention. This diagramis merely an example, which should not unduly limit the scope of theclaims herein. One of ordinary skill in the art would recognize othervariations, modifications, and alternatives. As shown, the presentinvention provides a method for monitoring a wireless communicationspace (e.g., office space, home, apartments, government buildings,warehouses, hot-spots, commercial facilities etc.) occupied by one ormore computer networks, e.g., wired, wireless. As shown, the methodincludes providing a geographic region, step 1. According to a specificembodiment, the geographic region can be within a building, outside of abuilding, or a combination of these. As an example, the region can beprovided in an office space, home, apartments, government buildings,warehouses, hot-spots, commercial facilities, etc. The method includesoperating a local area network in a selected portion of the geographicregion. The local area network (step 2) is commonly an Ethernet basednetwork for private use and may be for public use or any combination ofthese.

In a specific embodiment, the method monitors (step 3) a selected localgeographic region in the geographic region using one or more snifferdevices. The method includes detecting (step 4) a wireless activity fromat least one authorized device, at least one unauthorized device, or atleast one external device, within the selected local geographic regionusing at least one of the sniffer devices from the one or more snifferdevices. Preferably, the unauthorized device is one that is physicallyconnected to the network but does not belong to the network. That is,the unauthorized device has intruded the network according to preferredembodiments.

The method includes receiving (step 5) at least identity information(e.g., source information, destination information, MAC address)associated with the wireless activity in a classification process. Themethod also includes labeling (step 6) the identity information into atleast one of a plurality of categories, e.g., authorized, notauthorized, external, connected, not connected, and any combination ofthese. Of course, one of ordinary skill in the art would recognizevariations, modifications, and alternatives.

According to a specific embodiment, the method transfers (step 7) anindication associated with the identify information to a preventionprocess. As merely an example, once the unauthorized access point hasbeen detected, the method sends an indication of the unauthorized accesspoint to the prevention process. Preferably, the indication is sentalmost immediately or before the transmission of one or few more packetsby intruders, which is virtually instantaneously. Depending upon theembodiment, the method sends the indication via an inter process signalbetween various processes, which can be provided in computer codes.Alternatively, the method performs a selected function within the sameprocess code to implement the prevention process. Certain details of theprevention process can be found throughout the present specification andmore particularly below. Depending upon the embodiment, the method canperform other steps, as desired.

The above sequence of steps provides methods according to an embodimentof the present invention. As shown, the method uses a combination ofsteps including a way of detecting for an intrusion using wirelesscomputer networks. In preferred embodiments, the present invention alsoincludes an automated method for transferring an indication of anintrusion to a prevention process, which would preferably stop theintruding device before any security problems or the like. Many othermethods and system are also included. Of course, other alternatives canalso be provided where steps are added, one or more steps are removed,or one or more steps are provided in a different sequence withoutdeparting from the scope of the claims herein. Additionally, the variousmethods can be implemented using a computer code or codes in software,firmware, hardware, or any combination of these. Depending upon theembodiment, there can be other variations, modifications, andalternatives.

FIG. 1B is a simplified illustration of a sniffer apparatus according toan embodiment of the present invention. This diagram is merely anillustration, which should not unduly limit the scope of the claimsherein. One of ordinary skill in the art would recognize manyvariations, modifications, and alternatives. As shown, the inventionprovides a wireless sniffer apparatus including an automated intrusiondetection process. The apparatus has housing 11, which is characterizedby a length no greater than a first dimension, a width no greater than asecond dimension, and a height of no greater than a third dimension.Preferably, the housing has a length no greater than a first dimensionof about 40 centimeters, a width no greater than a second dimension ofabout 25 centimeters, and a height of no greater than a third dimensionof about 10 centimeters. The housing may be made of metal or plastic,which is suitable in strength and durable. The housing enclosescircuitry including chips, memory devices, wireless and wired networkinterface devices etc., which will be described in more detail below.

In a specific embodiment, the apparatus has a processing unit (e.g.,operable at a clock speed of more than 10 MHz) within the housing andone or more wireless network interface devices (e.g.,transmitter/receiver) within the housing and coupled to the processingunit. The apparatus has one or more antennas 12 coupled to the one ormore wireless network interface devices. Depending upon the embodiment,the one or more antennas are adapted to protrude outside of a portion ofthe housing or be within the housing or any combination of these. Theapparatus has at least one Ethernet network interface device (or otherlike device) within the housing and coupled to the processing unit and aleast one network connector 13 (e.g., RJ-45 socket) coupled to theEthernet network device. One or more memories (e.g., ROM, Flash, DRAM)are coupled to the processing unit. A code is directed to perform aprocess for detection of a wireless activity within a selected localgeographic region. According to a specific embodiment, the wirelessactivity is derived from at least one authorized device or at least another device. A code is directed to receiving at least identityinformation associated with the wireless activity from the detectionprocess in a classification process. A code is directed to labeling theidentity information into at least one of a plurality of categories inthe classification process. The apparatus also has a code directed totesting connectivity of at least the other device associated with thedetected wireless activity to a local area network within the selectedlocal geographic region. A first output indication (e.g., light,speaker) is on the housing. The first output indication is associatedwith the authorized device. A second output indication (e.g., light,speaker) is on the housing. Preferably, the second output indication isassociated with the other device. In a specific preferred embodiment,the visual output indications are provided using one or more of lightemitting diodes or LEDs 14A-14E provided on the housing. The apparatusalso has serial (e.g., RS-232) connector 15 and power input point 16.Further details of the hardware and software functionality can be foundthroughout the present specification and more particularly below.

Preferably, the sniffer device is easy to install on a given geographicregion, as illustrated by the simplified diagram of FIG. 1C. Here, themethod provides a method for installing one or more security devicesover a selected local geographic region. As shown in step 21, the methodincludes providing a wireless sniffer apparatus including an automatedintrusion detection process, such as those described herein. The methodincludes connecting the network connector of the sniffer apparatus tothe local area network, step 22. The method includes executing computercodes directed to testing connectivity of at least an other deviceassociated with the detected wireless activity to the local area networkas shown in step 23 and outputting either the first output indication orthe second output indication based upon the detected wireless activityas shown in step 24. Further details of various methods being carriedout in the sniffer apparatus including a block diagram can be foundthroughout the present specification and more particularly below.

FIG. 2 shows the logical flow of steps for wireless intrusion detectionaccording to the method of the invention. This diagram is merely anexample, which should not unduly limit the scope of the claims herein.One of ordinary skill in the art would recognize other variations,modifications, and alternatives. As shown, the first step 201 is tomaintain the list of active APs called the Active_AP_List. An active APis defined as the AP that was recently involved in the wirelesstransmission as the sender or the receiver. An active AP can be detectedby analyzing the wireless transmission on the radio channel captured bythe sniffer. For example, every AP in the Win network periodicallytransmits a beacon packet for the client wireless stations to be able toconnect to it. The beacon packet contains information such as clocksynchronization data, AP's MAC address (BSSID), supported data rates,service set identifiers (SSIDs), parameters for the contention andcontention-free access to the wireless medium, capabilities as regardsQoS, security policy, etc. In one embodiment, detection of beacon packettransmission from an AP is used to identify said AP to be an active AP.Beacon packet can be recognized from the type and subtype fields in the802.11 MAC header of the beacon packet. In alternate embodiments, activeAP can also be detected when any other wireless transmission (data,control or management packet) directed to or generating from it isobserved by the sniffer. Whenever an active AP is detected, it is addedto the Active_AP_List. If the Active_AP_List already contains entry forsaid AP, the corresponding entry is refreshed. Associated with eachentry in the Active_AP_List are a short timeout and a long timeoutvalues. After a short timeout, the corresponding entry is marked“inactive” and after a long timeout it is marked “historic”. The logicalflow of steps for maintaining the Active_AP_List is shown in FIG. 3.This diagram is merely an example, which should not unduly limit thescope of the claims herein. One of ordinary skill in the art wouldrecognize other variations, modifications, and alternatives.

The second step 202 is to classify the APs in Active_AP_List into atleast three categories, namely “authorized”, “unauthorized” and“external”. The authorized APs are defined to be the APs which areallowed to be connected to the LAN by the network administrator. Theunauthorized APs are defined to be the APs that are not allowed to beconnected to the LAN, but are still connected to the LAN. Theunauthorized APs pose a security threat. The external APs are defined tobe the APs whose active presence can be detected by the sniffers butthey are not connected to the LAN. For example, these can be neighbor'sAPs whose radio coverage spills into the physical space of interest. Theexternal APs do not pose a security threat. One or more tests areperformed to classify APs in the Active_AP_List into these categories.

The third step 203 is intrusion detection. When an unauthorized AP isdetected, intrusion alert is generated. Whenever any wireless stationattempting connection to or connected to unauthorized AP is detected,intrusion alert is generated. Once the intrusion alert is generated, themethod sends an indication of the AP and/or intruding wireless stationto a prevention process. Preferably, the indication is sent almostimmediately or before the transmission of one or few more packets byintruders. Depending upon the embodiment, the method sends theindication via an inter process signal between various processes, whichcan be provided in computer codes. Alternatively, the method performs aselected function within the same process code to implement theprevention process. Further details of the prevention process can befound throughout the present specification and more particularly below.

The fourth step 204 is intrusion prevention wherein subsequent tointrusion alert; action is taken to disable or disrupt any communicationbetween unauthorized AP and intruding wireless station. One embodimentof this step works by preventing or breaking the “association” betweenunauthorized AP and intruding wireless station. Association is theprocedure defined in 802.11 standard wherein the wireless station andthe AP establish a wireless connection between them. Techniques forpreventing or breaking the association include but are not limited tosending one or more spoofed “deauthentication” packets from one or moresniffers with AP's MAC address as source address with a reason code“Authentication Expired” to a particular intruding wireless station orto a broadcast address, sending one or more spoofed De-Authenticationpackets from one or more sniffers to unauthorized AP with intrudingwireless station's MAC address as source address with reason code “AuthLeave”, sending one or more spoofed “disassociation” packets from one ormore sniffers with AP's MAC address as source address to a particularintruding wireless station or to a broadcast address and sending one ormore spoofed disassociation packets from one or more sniffers tounauthorized AP with intruding wireless station's MAC address as sourceaddress. Another embodiment of this step involves continuously sendingframes from one or more sniffers with BSSID field containing MAC addressof unauthorized AP and a high value in network allocation vector (NAV)field. All client wireless stations of said AP including said intrudingwireless station then defer access to radio channel for the durationspecified in NAV field. This causes disruption to the communicationbetween said AP and said intruding wireless station. A number of otherembodiments such as inflicting acknowledgement (ACK) or packetcollisions via transmissions from the sniffer, destabilizing ordesynchronizing the wireless stations within the BSS (basic service set)of unauthorized AP by sending confusing beacon frames from the sniffercan also be used.

In the preferred embodiment of the method of invention, in step 202 atest called the “LAN connectivity test” is used to distinguish the APsin the Active_AP_List that are connected to the LAN (e.g., authorized orunauthorized) from those that are not connected to the LAN (e.g.,external). The logical flow of steps according to an embodiment of theLAN connectivity test is shown in FIG. 4. This diagram is merely anexample, which should not unduly limit the scope of the claims herein.One of ordinary skill in the art would recognize other variations,modifications, and alternatives. As shown in step 401, one or moremarker packets are transmitted to the LAN by the originating device. Theoriginating device can be a sniffer. For example, the sniffer cantransmit the marker packet to the concerned LAN via the Ethernet port.The marker packet has a peculiar format using which it can later beidentified by the intrusion detection system. The format can bedifferent for different marker packets. The marker packet may contain asequence number using which it can later be compared against the knownmarker packets. The marker packet may contain identity of theoriginating device. The marker packet is received by all or a subset ofAPs connected to the concerned LAN and transmitted by all or a subset ofthem on the wireless medium.

In step 402, one or more sniffers listen to one or more radio channelson which wireless communication can take place.

In step 403, at least one sniffer detects the transmission of at leastone marker packet on the radio channel. The marker packet is detected byanalyzing the format of the captured packet. If the AP transmits markerpacket on the radio channel without modifying it via encryptionprocedure all the format information in the detected packet is availableto the intrusion detection system for analysis for identifying markerpacket. If the AP transmits marker packet on the radio channel aftermodifying it via encryption procedure the intrusion detection system maynot be able to analyze all the format information in the detectedpacket. In this case, certain features of the packet format that areunaffected by encryption procedure are used for analysis. For example,the encryption procedure does not change the size of the data beingencrypted. Thus the size of detected packets can be used as a formatparameter to identify said packet as the marker packet.

Then in step 404 the identity of the AP that transmits the marker packetis determined from the 802.11 MAC header (for example from thetransmitter address or BSSID fields) of the packet transmitted on theradio channel.

In step 405, the AP that transmits the marker packet is declared to beconnected to the LAN. In a preferred embodiment, the corresponding entryin the Active_AP_List is marked as “connected to the LAN”.

In one embodiment of the above method, the marker packet is an Ethernetstyle packet addressed to the broadcast address, i.e., the value ofhexadecimal ff:ff:ff:ff:ff:ff in the destination address field ofEthernet MAC header. This packet will be received by all APs that arepresent in the LAN broadcast domain. The APs among these acting as layer2 bridges then transmit this broadcast packet on the wireless mediumafter translating it to the 802.11 style packet.

In alternate embodiment, the marker packet is an Ethernet style unicastpacket addressed to the MAC address of a wireless station associatedwith an AP. Said MAC address is inferred by analyzing the priorcommunication between said wireless station and said AP captured by thesniffer. This packet will be received by said AP if it is connected tothe concerned LAN. Said AP acting as layer 2 bridge then transmits themarker packet on the wireless medium after translating it to the 802.11style packet.

In another alternate embodiment, the marker packet is an IP packetaddressed to the IP address of a wireless station associated with an AP.Said IP address is inferred by analyzing the prior communication betweensaid wireless station and said AP that is captured by the sniffer. Thispacket will be received by said AP if it is connected to the concernedLAN and transmitted by said AP on the wireless medium after translatingit to the 802.11 style packet.

In yet an alternate embodiment, the marker packet is an IP packetaddressed to the broadcast IP address of the LAN.

In one embodiment, the marker packet is not actively injected in the LANby the intrusion detection system. Rather, one, or morebroadcast/multicast/unicast packets from the data traffic on the LAN areused as marker packets. The logic being if an AP is connected to thesame LAN as the sniffer, then at least the subset of the data trafficseen by the Ethernet port of the sniffer will be same as the datatraffic captured by the sniffer on the radio channel. Thus the sniffercompares the packet captured on the radio channel with the packetstransmitted over the wired LAN and captured by the sniffer's LANconnection port (Ethernet NIC) to identify a matching format.

The sniffer can detect the appearance of the marker packet on a specificradio channel only if the sniffer is tuned to said radio channel duringthe interval of transmission of the marker packet on said radio channel.It may thus be necessary to send marker packets in the LAN periodicallyand preferably at randomized intervals, so as to maximize theprobability that at least one sniffer gets an opportunity to detect atleast one marker packet transmitted by each AP connected to the LAN. Ina preferred embodiment, a sniffer originates a marker packet and thesame sniffer monitors wireless medium to detect the transmission of themarker packet on the wireless medium from one or more APs.

The logical flow of steps according to another embodiment of the LANconnectivity test is shown in FIG. 5. This diagram is merely an example,which should not unduly limit the scope of the claims herein. One ofordinary skill in the art would recognize other variations,modifications, and alternatives. This embodiment is particularly usefulto detect unauthorized APs that implement NAT (i.e., network addresstranslation) functionality unlike layer 2 bridge functionality though itis also useful for the latter. The test is also useful to detectunauthorized layer 2 bridge type APs (e.g., soft APs) that blockforwarding of broadcast packets from the wired LAN onto the wirelessmedium so as to evade detection by previous embodiment of the LANconnectivity test.

In step 501, the sniffer is tuned to the radio channel on which an APoperates. In step 502, the sniffer establishes wireless connection withsaid AP. This typically involves listening to AP's beacon packet andsubsequently performing “association” procedure with said AP asdescribed in IEEE 802.11 standard. Subsequent to association, theparameters for IP connection are assigned to the radio interface of thesniffer. A preferred method to assign IP connection parameters is forthe sniffer to perform DHCP (i.e., dynamic host configuration protocol)request/response transactions over the wireless connection establishedwith AP. These parameters comprise at least of the IP address for theradio interface of the sniffer. The DHCP is described in RFC 2131standard of the Internet Engineering Task Force (IETF).

In an alternate embodiment, in step 502 rather than establishing a newassociation with the AP, the sniffer reuses an existing associationbetween the AP and a wireless station associated with the AP. For this,the sniffer detects the parameters of an existing association betweenthe AP and the wireless station associated with the AP. The parametersinclude, among others, the MAC address of the associated wirelessstation. The sniffer may also determine the IP address and the TCP orUDP port number of the wireless station by monitoring the packetstransmitted or received by the station.

In step 503, the sniffer sends one or more marker packets to the AP overthe wireless connection newly established or already existing asapplicable depending on the embodiment of step 502. Preferably, themarker packet is addressed to the sniffer itself. Various preferredembodiments for this step are now described.

In one embodiment of step 503, the marker packet is UDP (i.e., userdatagram protocol) packet. UDP is the transport layer protocol used bycomputers in the IP network to exchange data. It is described in RFC 768standard of the IETF. In a preferred embodiment, UDP marker packet hassource IP address as the IP address of the radio interface of thesniffer. In an alternative embodiment wherein step 502 reuses existingassociation, preferably the UDP marker packet has the source IP addressand the source UDP port number same as the corresponding values detectedin the packets transmitted by the wireless station whose association isbeing reused by the sniffer. The destination IP address in the UDPpacket is the IP address of the wired (Ethernet) interface of thesniffer.

In another embodiment of step 503, the marker packet is a TCP (i.e.,transmission control protocol) packet. The TCP is a transport protocoldescribed in RFC 793 standard of the IETF. It is used by computers in IPnetwork for reliable exchange of data. In a preferred embodiment, TCPmarker packet is TCP SYN packet. In alternate embodiment, it can be anypacket in TCP format. In a preferred embodiment, TCP marker packet hassource IP address as the IP address of the radio interface of thesniffer. In an alternative embodiment wherein step 502 reuses existingassociation, preferably the TCP marker packet has the source IP addressand the source TCP port number same as the corresponding values detectedin the packets transmitted by the wireless station whose association isbeing reused by the sniffer. The destination IP address in the TCPpacket is the IP address of the wired (e.g., Ethernet) interface of thesniffer.

In yet another embodiment of step 503, the marker packet is any layer 2style frame. In a preferred embodiment, the source address in said layer2 frame is the MAC address of the radio interface of the sniffer. In analternative embodiment wherein step 502 reuses existing association,preferably the source address in the layer 2 frame is the MAC address ofthe wireless station whose association is being reused by the sniffer.The destination address in the layer 2 frame is the MAC address of thewired (e.g., Ethernet) interface of the sniffer.

In yet another embodiment of step 503, the marker packet is addressed tothe broadcast address. If the sniffer detects that the IP addressassigned to its radio interface is in the domain of addresses assignedto the wired LAN, the marker packet can be addressed to IP broadcastaddress in said domain of addresses. The IP broadcast address isconstructed by using all binary ones in the host address part and usingthe network number of said wired LAN in the network address part of theIP address. Alternatively, layer 2 format marker packet can be addressedto the MAC broadcast address, which is hexadecimal ff:ff:ff:ff:ff:ff.

If said AP is indeed connected to the LAN, it will forward marker packetfrom the wireless connection to the LAN and thus the marker packet willbe received at the sniffer in step 504.

Subsequently, said AP is declared to be connected to the LAN in step505. Alternatively, if the AP is not connected to the LAN, the markerpacket will not be received at the sniffer and said AP is then declaredunconnected to the LAN in step 506 according to a specific embodiment.

The logical flow of steps according to another embodiment of the LANconnectivity test is shown in FIG. 6. This diagram is merely an example,which should not unduly limit the scope of the claims herein. One ofordinary skill in the art would recognize other variations,modifications, and alternatives.

For this, in step 601 the sniffer is tuned to a radio channel. Thesniffer listens to the radio channel to detect the transmission of oneor more “trigger” packets. In a specific embodiment, the trigger packetsindicate the current state of ongoing communication between an AP and awireless station. Knowing this enables preparing and sending markerpacket so that it is almost indistinguishable from the packetsconstituting the ongoing communication between the AP and the wirelessstation. This makes it difficult for certain APs, for examplecompromised, software controlled or non-standard, to evade detection bymarker packet test.

When the transmission of one or more trigger packets is detected in step602, the identity of the AP that is the source or destination of thetrigger packets is determined in step 603 from the transmitter addressor the receiver address in the 802.11 MAC header of the trigger packets.

Depending upon the type of trigger packets an optional step 604 isperformed to determine if said AP is suspected to be not authorized(i.e. it can be unauthorized or external). For example an AP in theActive_AP_List that has not previously responded to any LAN connectivitytest is suspected to be not authorized. Or, an AP whose behavior(contents of beacon frame, MAC address, authentication and encryptionmethods etc.) does not match the behavior known of the authorized APs issuspected to be not authorized.

In step 605 one or more marker packets are constructed based on the typeof trigger packets and information contained therein. The marker packetsare transmitted in the LAN in step 606. The sniffer continues to listento the same radio channel to detect the transmission of at least onemarker packet on the radio channel by said AP. If the marker packettransmission is detected before a timeout occurs, said AP is declared tobe connected to the LAN. Alternatively, the AP is declared unconnectedto the LAN according to a specific embodiment.

In one embodiment of the LAN connectivity test using trigger packets,the trigger packets and the marker packets are transmission TCP packets.TCP is used by computers in Internet Protocol (IP) network for reliableexchange of data. TCP provides acknowledgement-based data deliverywherein lost pieces of data are recovered via retransmissions. The TCPalso uses window-based congestion control algorithm so as to dynamicallyadapt to the available bandwidth between the communicating computers. Anumber of desirable Internet applications such as HTTP, file transfer,email, remote login, etc., are performed using TCP as transportprotocol.

Suppose the sniffer detects transmission of a TCP packet from a wirelessstation to the AP (called uplink direction) that is suspected to be notauthorized. TCP packet is identified by examining the header fields ofdetected packet transmission. Specifically, for the TCP packet the valueof “Type” field in 802.2 frame header is hexadecimal 0800 and the valueof “Protocol” field in the IP header is hexadecimal 06. Then the markerpacket is constructed as a TCP packet and in one embodiment the variousfields in the marker packet (step 605 above) are set as follows:

Swap the source and destination addresses in the Ethernet, IP and TCPheaders of trigger packet to get source and destination addresses in thecorresponding headers of marker packet.

Set the TCP payload in marker packet such that it can later beidentified by the intrusion detection. Let L denote the size of payloadin number of octets.

Let x1 denote the value of “sequence number” field in the TCP header oftrigger packet and x2 denote the number of octets of TCP payload in thetrigger packet. Then set “acknowledgement number” field in the TCPheader of marker packet equal to (x1+x2).

Let x3 denote the value of “acknowledgement number” field and x4 denotethe value of “window” field in the TCP header of trigger packet. Thenset the value of “sequence number” field in the TCP header of markerpacket to a value that is between (x3−1) and (x3+x4−L).

Other fields in the marker packet are set according to standard practiceused by various implementations of corresponding protocols. Among these,values for some of the fields can be more judiciously chosen if thesniffer has also recently captured a TCP packet of the same flowtransmitted by said AP to said wireless station (downlink). For example,the value of “window” field in the marker packet can be set equal to orclose to the value of “window” field in the recently captured downlinkTCP packet. Similarly, the value of “Identification” field in the IPheader of marker packet can be set greater than the value of“Identification” field in the recently captured downlink TCP packet.

Suppose that the sniffer detects downlink TCP packet. Then the markerpacket is constructed as a TCP packet and in one embodiment the variousfields in the marker packet (step 605 above) are set as follows:

a. Swap source and destination addresses in the Ethernet, IP and TCPheaders of trigger packet to get source and destination addresses in thecorresponding headers of marker packet.

b. Set the TCP payload in marker packet such that it can later beidentified by the intrusion detection. Let L denote the size of payloadin number of octets.

c. Let x1 denote the value of “sequence number” field in the TCP headerof trigger packet and x2 denote the number of octets of TCP payload inthe trigger packet. Then set sequence number field in the TCP header ofmarker packet to a value greater than (x1+x2−1). If the sniffer hasrecently captured uplink TCP packet of the same flow and thus theintrusion detection has the knowledge of value of “window” field inrecent uplink packet, the value of “sequence number” field in markerpacket should be chosen so that it is also less than (x1+window−L+1).

d. Other fields in the marker packet are set according to standardpractice used by various implementations of corresponding protocols.Among these, values for some of the fields such as “window” field in TCPheader and “Identification field in IP header can be more judiciouslychosen if the sniffer has also recently captured uplink TCP packet ofthe same flow.

In another embodiment of the LAN connectivity test using triggerpackets, the trigger packet is DHCP request packet and the marker packetis DHCP response packet.

In the preferred embodiment of the method of invention, in step 202 oneor more feature criteria are used distinguish the APs in theActive_AP_List that are authorized by the network administrator fromthose that are not authorized. The latter include unauthorized andexternal APs. The method of invention works by inferring one or morefeatures of an AP via analysis of the packets captured by the snifferand comparing them with the features of the authorized APs. If thediscrepancy is detected, said AP is deemed to be not authorized.

A number of features of an AP can be inferred by analyzing one or morebeacon packets transmitted by the AP. These features include but notlimited to the vendor information (indicated by the first three bytes ofthe MAC address of the AP), the observed beacon interval and values ofvarious fields (according to basic 802.11 and its enhancements including802.11e, 802.11i, 802.11k and others) in the beacon packet such asbeacon interval, SSID, capabilities information, radio parameters,various information elements (IEs) etc.

Some other features of an AP can be inferred by analyzing the sequenceof packets flowing between the AP and a wireless station. Most notably,the flow of authentication and association procedure (WEP, WPA, TKIP,RSN etc.) can be monitored by the sniffer to determine if it isconsistent with that of an authorized AP.

The feature set of authorized APs can be provided to the intrusiondetection system by the network administrator. Alternatively, theintrusion detection system can learn the authorized feature set bydetecting APs and their associated feature set in the operationalnetwork or laboratory environment. In the former case, the networkadministrator merely indicates to the intrusion detection system as towhich of the detected APs are authorized APs.

The sniffer may perform active probing to infer the features of an AP.For example, the sniffer attempts to establish a wireless connectionwith the AP which typically involves authentication and associationprocedure. The sniffer is provided with the credentials to be usedduring the authentication procedure. For example, the credentialsinclude but not limited to password, digital certificate, security key,etc. If the sniffer succeeds in establishing the wireless connectionwith the AP, the AP may be declared as authorized. This test is evenmore effective for the authentication schemes, such as extensibleauthentication protocol transport layer security (EAP TLS), whichperform mutual authentication. Depending upon the embodiment, thepresent invention can implement the various methods using certainsystems, which are described in more detail below.

One embodiment of the intrusion detection system according to presentinvention is described with reference to FIG. 7. The system comprises adetection module 702, a classification module 704 and a preventionmodule 706, each of the modules comprising one or more computerexecutable codes. The various codes can be running in one or morecomputer processes.

The detection module 702 is directed to performing tasks associated withdetecting wireless activity. In a specific embodiment the detectingcomprises capturing, decoding and processing the wireless activity. Thedetecting may further comprise filtering and summarizing the informationassociated with or derived from the wireless activity. The detectionmodule is further directed to transferring at least identity informationassociated with the detected wireless activity to the classificationmodule. In a specific embodiment the detection module transfersadditional information associated with the detected activity such asinformation derived from beacon packet, marker packet, authenticationpacket and other packets to the classification module. Theclassification module 704 is directed to performing tasks associatedwith receiving and labeling the identity information associated with thewireless activity into at least one of a plurality of categories. In aspecific embodiment, the classification module analyzes the additionalinformation associated with the wireless activity received from thedetection module for the sake of labeling the identity information. Theclassification module is further directed to performing tasks associatedwith transferring indication associated with the identity information tothe prevention module 706. In one specific embodiment, the indication isan intrusion alert. In a specific embodiment, intrusion alert isgenerated when an unauthorized AP and/or intruding wireless station isdetected by the classification process.

Another embodiment of the intrusion prevention system according topresent invention is described with reference to FIG. 8. The systemcomprises a providing module 801, a transferring module 802, anoutputting module 803, a receiving module 804, a processing module 805and an identifying module 806. Each of the modules comprises one or morecomputer executable codes. The providing module 801 prepares the markerpacket with a given format. In a specific embodiment, the providingmodule resides within the originating device (e.g., sniffer). Thetransferring module 802 transmits the marker packet to one or more APsover the LAN. In a specific embodiment the transferring module resideswithin the originating device (e.g., sniffer). The outputting module 803transmits the marker packet from the AP to the wireless medium. In aspecific embodiment, the outputting module resides within the AP. Thereceiving module 804 is directed to receiving wireless activityassociated with the marker packet using at least one sniffer. Theprocessing module 805 is directed to processing the wireless activityinformation to identify the marker packet. In a specific embodiment, theprocessing module analyzes the format information in the receivedwireless activity to identify the marker packet. The identifying module806 is directed to determining the identity information associated withthe wireless activity associated with the marker packet. In a specificembodiment, the identifying module determines the source AP of thewireless activity associated with the marker packet. In another specificembodiment, the receiving module, the processing module and theidentifying module are provided within the sniffer device.

Another alternative embodiment of the intrusion detection system isdescribed below with reference to FIG. 9. In this embodiment, thedetection, classification and prevention modules are provided within thesniffer device. The sniffer also provides and transfers a maker packet.The sniffer further receives the wireless activity associated with themarker packet, processes said activity to identify the marker packet andidentifies the AP that transmits marker packet on the wireless medium.This embodiment in particularly advantageous because it allowsdeployment of standalone sniffer devices (e.g., as appliances).

Accordingly, the sniffer appliance device comprises a CPU 901 adapted toexecuting computer codes and a memory 902 that stores computer codes anddata. The computer codes stored in the memory comprise at least thecodes for detection, classification and prevention modules and the codesadapted to perform communication between said modules. The computercodes stored in the memory further comprise the codes for providing amarker packet, transferring a marker packet, receiving a wirelessactivity associated with the marker packet, processing said wirelessactivity to identify the marker packet and identifying the AP thattransmits the marker packet on the wireless medium. The snifferappliance device comprises one or more WiFi NICs 903 connected to one ormore antennas 904. The WiFi NICs performs the tasks associated withreceiving the wireless activity (e.g., listening to and capturing thepacket transmissions occurring over the wireless medium in accordancewith 802.11 standard) as well as initiating the wireless activity (e.g.,transmitting packets in accordance with 802.11 standard). The EthernetNIC 905 is also provided that enables connecting the sniffer appliancedevice to the LAN via Ethernet jack 06 (e.g., RJ-45 socket). TheEthernet jack 906 may alternatively and additionally be used to connectthe sniffer appliance to a PC for configuration purposes. Alternatively,a serial communication interface (e.g., RS-232) 912 is used to connectthe sniffer appliance to a PC for configuration purposes. The variouselectronic components are connected together using data transfer bus907. The sniffer device can provide visual indication about detectedwireless activity by means of one or more light bulbs or light emittingdiodes 908 provided on the device panel 910. Optionally or in additionto, an electronic screen such as for example LCD screen 909 is providedon the device panel for providing visual indication and/or textualmessages. In a specific preferred embodiment, the indication isassociated with a device type selected from, but not limited to, a noactive device type, at least one active device type, all authorizeddevice type, at least one unauthorized device type, and at least oneunauthorized device in active communication type.

After the sniffer device is powered on, the light bulb 908 turns whitein color if Active_AP_List is empty. The bulb turns yellow when at leastone active AP is detected. After the sensor device is connected to thewired LAN (e.g., using Ethernet jack 906), it can start executing steps202 and beyond shown in FIG. 2 according to the specific embodiment ofthe method of invention. If only authorized APs connected to the LAN aredetected, the bulb turns green. If the unauthorized AP is detected instep 202, the light bulb turns red in color. If the wireless stationattempting to connect or connected to the unauthorized AP is detected instep 203, the light bulb turns flashing red. Alternatively, the variousvisual indications are provided via combination of light bulbs from aplurality of light bulbs provided on the device panel (e.g., one foreach event). Other indications may also be provided via one or morelight bulbs. Yet alternately, such indications can also be given inaudio form, for example via different types of alarm sounds from thespeaker (not shown in FIG. 10). An on/off switch 911 may be provided onthe sniffer device panel that enables turning the intrusion defense step204 on or off. Alternatively, the on/off switch for activating anddeactivating the intrusion defense is software controlled. Yetalternatively, the step 204 is executed automatically after intrusiondetection.

The above methods and systems are provided according to embodiments ofthe present invention. As shown, the method uses a combination of stepsincluding a way of detecting for an intrusion using wireless computernetworks using a sniffer apparatus. In preferred embodiments, thepresent invention also includes an apparatus having an automated methodfor transferring an indication of an intrusion to a prevention process,which would preferably stop the intruding device before any securityproblems or the like. Many other methods and system are also included.Of course, other alternatives can also be provided where steps areadded, one or more steps are removed, or one or more steps are providedin a different sequence without departing from the scope of the claimsherein. Additionally, the various methods can be implemented using acomputer code or codes in software, firmware, hardware, or anycombination of these. Depending upon the embodiment, there can be othervariations, modifications, and alternatives.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

What is claimed is:
 1. Apparatus for wireless communication including anautomated intrusion detection process, the apparatus comprising: aportable housing, the housing having a length no greater than 1 meter, awidth no greater than 1 meter, and a height of no greater than 1 meter;a processing unit within the housing; one or more wireless networkinterface devices within the housing and coupled to the processing unit;at least one Ethernet network interface device within the housing andcoupled to the processing unit; at least one network connector coupledto the Ethernet network interface device; and one or more memorieswithin the housing and coupled to the processing unit, the one or morememories including: a code directed to perform a process for detectionof a wireless activity within a selected local geographic region, thewireless activity being derived from at least one authorized device orat least an other device; a code directed to receiving at least identityinformation associated with the wireless activity from the detectionprocess in a classification process; and a code directed to labeling theidentity information into at least one of a plurality of categories inthe classification process.
 2. The apparatus of claim 1 furthercomprising at least one indicator provided on the housing, the indicatorbeing coupled to the processing device, the indicator being able tooutput one or more indications based upon at least the identityinformation.
 3. The apparatus of claim 2 further comprising a codedirected to transferring an indication associated with the identifyinformation to a prevention process, the code being in one or more ofthe memories.
 4. The apparatus of claim 3 further comprising a codedirected to performing the prevention process.
 5. A wireless snifferapparatus including an automated intrusion detection process, theapparatus comprising: a housing, the housing having a length no greaterthan a first dimension, a width no greater than a second dimension, anda height of no greater than a third dimension; a processing unit withinthe housing; one or more wireless network interface devices within thehousing and coupled to the processing unit; one or more antennas coupledto the one or more wireless network interface devices, the one or moreantennas being adapted to protrude outside of a portion of the housingor being adapted to be completely within the housing or a portion ofthey one or more antennas are within the housing and a portion of theone or more antennas are outside of the housing; at least one Ethernetnetwork interface device within the housing and coupled to theprocessing unit; at least one network connector coupled to the Ethernetnetwork interface device; and one or more memories within the housingand coupled to the processing unit, the one or more memories including:a code directed to perform a process for detection of a wirelessactivity within a selected local geographic region, the wirelessactivity being derived from at least one authorized device or at leastan other device; a code directed to receiving at least identityinformation associated with the wireless activity from the detectionprocess in a classification process; and a code directed to labeling theidentity information into at least one of a plurality of categories inthe classification process; and a code directed to testing connectivityof at least the other device associated with the detected wirelessactivity to a local area network within the selected local geographicregion; a first output indication coupled to the housing, the firstoutput indication being associated with a first device type; and asecond output indication coupled to the housing, the second outputindication being associated with a second device type.
 6. Apparatus ofclaim 5 further comprising a third output indication coupled to thehousing, the third output indication being associated with a thirddevice type.
 7. Apparatus of claim 5 wherein the processor having aclock speed of more than 10 MHz.
 8. Apparatus of claim 5 wherein the oneor more memories comprises at least a 8 Megabit Flash Memory. 9.Apparatus of claim 5 wherein the one or more memories comprises at leasta 16 Megabit DRAM device.
 10. Apparatus of claim 5 wherein theprocessing unit is operable with a Linux operating system or a real timeoperating system.
 11. Apparatus of claim 5 wherein the first dimensionis less than 40 centimeters, the second dimension is less than 25centimeters, and the third dimension is less than 10 centimeters. 12.Apparatus of claim 5 wherein the one or more wireless interface devicescomprise a first wireless interface device and a second wirelessinterface device, whereupon the first wireless device and the secondwireless device are operable during a predetermined portion of time,each of the first wireless device and the second wireless device beingunder control of a software.
 13. Apparatus of claim 5 wherein thehousing is free from a hard disk drive unit.
 14. Apparatus of claim 5wherein the housing is free from any PC type keyboard interface device.15. Apparatus of claim 5 wherein the sniffer is characterized as asensor and is operable in a standalone manner.
 16. A method forinstalling one or more security devices over a selected local geographicregion, the method comprising: providing a wireless sniffer apparatusincluding an automated intrusion detection process, the apparatuscomprising: a housing, the housing having a length no greater than afirst dimension of about 40 centimeters, a width no greater than asecond dimension of about 25 centimeters, and a height of no greaterthan a third dimension of about 10 centimeters; a processing unit withinthe housing; one or more wireless network interface devices within thehousing and coupled to the processing unit; one or more antennas coupledthe wireless network interface devices, the one or more antennas beingadapted to protrude outside of a portion of the housing or being adaptedto be completely within the housing or a portion of the one or moreantennas are within the housing and a portion of the one or moreantennas are outside of the housing; at least one Ethernet networkinterface device within the housing and coupled to the processing unit;at least one network connector coupled to the Ethernet network device;and one or more memories within the housing and coupled to theprocessing unit, the one or more memories including: a code directed toperform a process for detection of a wireless activity within a selectedlocal geographic region, the wireless activity being derived from atleast one authorized device or at least an other device; a code directedto receiving at least identity information associated with the wirelessactivity from the detection process in a classification process; a codedirected to labeling the identity information into at least one of aplurality of categories in the classification process; and a codedirected to testing connectivity of at least the other device associatedwith the detected wireless activity to a local area network within theselected location geographic region; a first output indication coupledto the housing, the first output indication being associated with afirst device type; and a second output indication coupled to thehousing, the second output indication being associated with a seconddevice type; connecting the network connector to the local area network;executing at least a portion of the code directed to testingconnectivity of at least the other device associated with the detectedwireless activity to the local area network; and outputting either thefirst output indication or the second output indication based upon thedetected wireless activity.
 17. The method of claim 16 wherein the firstoutput indication and the second output indication comprise respectivelya first visual indication and a second visual indication.
 18. The methodof claim 16 wherein the first output indication and the second outputindication comprise respectively a first audio indication and a secondaudio indication.
 19. The method of claim 1 wherein the first devicetype is associated with a no active device detected state, the seconddevice type is associated with at least one active device detectedstate; and further comprising outputting a third output indicationassociated with a third device type, the third device type beingassociated with an all authorized device state and/or outputting afourth output indication associated with a fourth device type, thefourth device type being associated with an unauthorized device stateand/or outputting a fifth output device indication associated with afifth device type, the fifth device type being associated with anunauthorized device state actively communicating.
 20. Apparatus forsniffing wireless communication including an automated intrusiondetection process, the sniffer apparatus comprising: a movable housing,the housing having a length, a width, and a height; a processing unitwithin the housing; one or more wireless network interface deviceswithin the housing and coupled to the processing unit; at least oneEthernet network interface device within the housing and coupled to theprocessing unit; at least one network connector coupled to the Ethernetnetwork interface device; and one or more memories within the housingand coupled to the processing unit; wherein the processing unit adaptedto direct a process for detection of a wireless activity within aselected local geographic region, the wireless activity being derivedfrom at least one authorized device or at least an other device; whereinthe processing unit adapted to receive at least identity informationassociated with the wireless activity from the detection process in aclassification process; and wherein the processing unit adapted to labelthe identity information into at least one of a plurality of categoriesin the classification process.